The alarming spread of illegal squatter settlements has aid groups fearful of a looming social crisis, one which a senior United Nations official considers “the greatest humanitarian problem facing Iraq”.

Recent reports from two international agencies found that of Iraq’s 1.5 million internally displaced people, or IDPs, at least 500,000 have been forced to dwell in squalid squatter camps without access to health care or public services.

The United Nations High Commissioner for Refugees, UNHCR, has recorded a sharp increase in squatters since 2009, and activists are demanding the United States and UN stem the problem before it surges out of control.

“We registered 160,000 [squatters] in Baghdad a year ago and this March the number was up to 260,000. This is only for Baghdad, we haven’t published figures for the whole country yet but it’s at least up from 400,000 to 500,000 for the time being,” Daniel Endres, Iraq representative of UNHCR, said.